How to suggest sex nicely

What is the most polite, but direct, way to offer or ask someone for sex?

Asking someone out right for sex can be a bit awkward and could end in failure in random encounters. I mean the best worlds I could give you to say are "you are really _____ (stunning, attractive, beautiful, wonderful)." You put your intentions into suggestive words and body language. If they aren't feeling it, then stop and move on.

To answer this question better more info is needed.

1) is this a general or personal Q? (I answered generally above)
2) is this in relation to someone you know?
3) what is your and the other persons relationship status? (single, married, dating)
4) do you want a relationship or just a hook-up?
5) if they're under the age of consent, then know that there are legal consequences.

Would you like some penis?

Ask if they would consider you to be a "Friend with benefits"

Is this the hook-up kind of sex we're talking about?

Like this.

Context is important here.

I don't think forced sex is going to work out. And i don't mean rape but more like if you ask someone if they want to have sex with you and then they say yes. It would be so awkward... or at least i think so. I'd let it come natrually if I were you. If you havn't done it before with the person just go with the flow. show in body language that you want him/her.
My tip is: take it slow..

Okay first off, don't walk up and ask for it right off the back, I suggest mingling with him/her first. If you intend to have one night stand which is what I'm assuming, say something along the lines as "I think you're a beautiful woman. Would you like to come back to my place?"

Something like that.

"I WANT TO GIVE YOU THE HONOR OF STICKING MY PEEPEE INTO YOUR VAGOO!"

That would depend on what type of relationship you have with that person.

Make sure to grunt like a chimp while you do this

Just be sexual about it I suppose. Like take chef from South Park I suppose.

Or you can be direct and just

Just say, "wanna fuck?" You dumb shits always over complicate everything.

I would usually be as direct as possible. If you skip around and try to tiptoe around the topic, it can cause some confusion later on.